In the clip above, it’s calm at first as April’s fiancé, Matthew, walks in from the storm after his rig stalled out in the water and starts to help. Then suddenly, the couple — along with Owen, Jackson, Callie, and Bailey — watch in horror as a bus soars through the air, skids across the street, flips over, and then sets on fire outside of the hospital. Will it explode? How many people must they save? We’ll have to wait and see.

Check out the sneak peek to see them all rush to help, and then hit the comments with your thoughts and theories!

The Season 9 finale of Grey’s Anatomy airs Thursday, May 16, 2013 at 9 p.m. ET/PT on ABC.